Cutter head



H.A I. MITCHELL- cuTTER HEAD; APPLICATION FILD APR. 22,1921.

Patented Feb. 7, 1922.

IIIIIII lm, IIIIHIIHIHH IIIIIIII? I 'Y UNITED STATES PATENT OFFICE.

HARRISON J.. MITOHELLOF SEATTLE, WASHINGTON, ASSIGNOR To P. B. kYarns MACHINE COMPANY, or BELOIT, WISCONSIN, a CORPORATION OR WISCONSIN.

' CUTTER HEAT-3.

Specification of Letters Patent.

Patented Feb. 7, 1922.

Application filed April 22, 1921. Serial No. 463,483.

To @ZZ/whom t may concern:

Be it known that I, HARRISON J. MITCHELL, a citizen of the United States, residing at Seattle, in the county of King and State of Washin ton, have invented certain new and useful mprovements in Cutter Heads, of which the following is a specification.

My invention relates to simple and improved means for holding or clamping the cutting knives or blades on a cutter-head for woodworking machines.

One object of the invention is to provide an appliance of this general type in which cutter knivesof different widths or lengths may be usedv and firmly held in position by the same adjustable clamping means, hence not requiring the interchange of any part-s for knives of different dimensions.

A further or additional feature of the invention resides in simple and eiiicient means for holding wide or long cutter knives between their edges or ends in such a waythat the cutting edge of the knife will be maintained straight veven though the knife may have been slightly sprung or distortedy as during tempering.

Another purpose of the invention is the provision of a structure of this vcharacter which is simple in form, composed of few parts, inexpensive to produce, and effective and reliable in results.

To enable those skilled in this art to have a full and complete understanding of the invention both from structural and functional standpoints, l have illustrated two desirable and preferred embodiments of thevsame in the accompanying drawing forming a part of this specification and to which reference should be had in connection with the following detailed description.

In this drawing, throughout the-severalviews of which like reference characters refer to the same parts.

Figure 1 is an end viewof the improvedy cutter head; v

Figure 2 is a face view of the same; Figure 3 is a section through one of the knife retaining clamps;

Figure 4i is a face view of'a wider knife Figure 5 is a. fragmentary longitudinal` section showing the manner of maintaining such longer or wider knife in place on the cutter head; and

Figure 6 is a fragmentary section showing the holding of the cutter knife between bev- Referring to this drawing, it will be per-y ceived that the appliance comprises a somewhat elongated cutter-head or main-bo dy 10, having a central round aperture 11 for the reception of the drive shaft, not shown, such member having a plurality of, in the present instance six, surfaces 12 disposed lengthwise the head with intervening longitudinal grooves or recesses 13 and vadapted 'to be fitted or provided each with one cutter blade or knife 14,-these several surfaces being at an angle to and spaced from one another and arranged around the entire head. i

Stated somewhat otherwise, the cutterhead Lis of general, but not exact, hexagonal form, its six faces being slightly separated from one another as indicated.

The number of such faces, and accordingly the number of cutters employed, may be varied as circumstances dictate, being either greater or less than the six specified, the inventionV in no way being limited in this respect. f

Secured flat against one end of this main-Y body by Vseveral fastening screws 15, or by other appropriate means, is a plate 16 having siX radiating ears or projections 17 in register with and extending outwardly beyond the corresponding, bit-receiving surfaces 12 referred to, each of such rears having a sloping or undercut face 18 extending inwardly from its outer end to the surface 12.

Each of 'such projections or lugs constitutes ain undercut or beveled abutment wall against whichV the correlative or complementary, sloping, side edge portion 19 of the cutter blade -is adapted to bear', these interfltting parts preventing dislodgment or displacement of the `cutter blade.

For Athe'greater portion of its length or for Itsentirelength, each of the six angu-Y tured clamp 28 having a beveled or undercut face 22 adapted toV bear on and Overlie the correspondingly sloping side edge'por- Vor inner face along its opposite edge having a rib or heel 24 designed to fit in any one of the spaced notches or channels of the ratchet, as is perhaps most clearly depicted in the upper partl of VFigure 2.

Each clamp is held in place by a bolt 25 extended through its hole and having its square head 26 received and adjustable lengthwise in the groove 2O and its coacting, external, readily-accessible nut 27, the tightening and loosening of which may be easily effected by turningit in the usual manner to fasten and release the associated sharp edged cutter. l l

In tightening the nut an extremely effective Wedge and clamping action on the lcutter Lblade is obtained, all as will be readily understood by those skilled in the art,

whereby the proper and effective holding of the cutter knife inposition under all-condi-` tions of severe service is assured. Y

, Stated otherwise, the tightening or 'turn-v ing of the nut forces the clamp inwardly, and, by means of the coacting beveled surg faces, the knife is pushed or forced firmly in under the overhanging abutment wall 17 .Also in screwing up the nut to fasten the clamp, the rib or heel of the latter acts somewhat yas a fulcrum about which the clamp-- ing member has a slight turning movement, and the cooperating sloping faces of the cutter and` clamp make certain that such heel and rib will be in proper engagement with the ratchet tooth on which it bears.

Due to the fact that the clamp and its fastening bolt are capable of adjustment lengthwise'the face l2 of the cutter-head, it is adapted to securely hold cutter blades 'of different widths, the notches of Ythe ratchet being sufficiently near to one another so that Y one is lalways available for all transverse 2 to facilitate the inward movement of the dimensions of the cutter knives which the headisadapted and designed to employ.

'In order to insure the correct and effective cooperation of theratchet teeth with the rib' or heel `of the clamp, the inner faces of the ratchet teeth, that is those surfaces-facing the plate 16, are preferably, thoughv not necessarily, vat right angles to they axis 'of the head, whereas the outer faces of the teeth are sloping Vor inclined as `shown in Figure clamps thereover and to Igive the teeth broader bases.

When wider knives or cutters are used, they are ordinarily provided with a central slot or recess 29, as illustrated in Figure i4, to receive an additional holdingor clamping bolt 30 having its head in the groove 20 and itsnut bearing on the outer face of the knife to maintain the central portion firmly in place.k

If in tempering or for any other reason the cutter orknifehas been slightlysprung out of true, such middle bolt will draw the blade down flat onto the cutter head thereby making certain that 'the comparatively long or wide knife will be maintained straightY throughout its entire length.

Although I have illustrated and described only two embodiments of the invention', it is to be understood that the latter is susceptible of a variety of incorporations in physical form and that many mechanical changes may be made `in the structures depicted and described without departure from the heartand essence of therinvention and Y sev opposite side'edge portion lof the cutter and designed to fit inlany'one of saidV notches depending upon the width of the cutter, 'and means to maintain said clamp in anyone of said notches to hold the cutter in operative position. l y

2. In a cutter-head of the character described, the combination of a main body having an abutment wall to engage one side edge portion `of 'the cutter and a series of spaced notches at different distances :from said wall, a clamp adapted to engage the oppositeside edge portion of the cutter and designed to fit in Vany one of said notches de-y pending upon the width ofthe cutter, and screw threadedv means to vmaintain "said clamp in any one/of said notches to hold the cutter inoperative position.

`3. In a cutter-head of the character scribed, the combination ofa'rnain bodyhavin vanundercut labutment Wa-'ll to'fengage one si e edge portion ofthe cutter and -a 'series of spaced notches at different distances from 'said abutment wall, afclainp having an un- Ydercut part to engage the-oppositeside edge portion of the cutter and aving :aheelto fit in any 'oneofsaid notches depending upon the width of the cutter, and screw threaded means to lmaintain said clamp 'heel 'in any one of said notches and 'to cause the clamp to hold the cutter inoperative position. p

4. In acutter-hea'd `of the character de scribed, the combination 4of a Vrmain bodyhaving an undercut abutment wall toengageone side edge portion sof 'the cutter and a jseries 'l of spaced notches at diferentdistances from saidV abutment wall,'a clamp 'havingfan'undercut part to engagethe opposite side edgeV portion of the cutter and having a heel to it in any one of said notches depending upon the Width of the cutter, and screw threaded means adjustable toward and from said Wall With the clamp to maintain the clamp heel in any one of said notches and to cause the clamp to hold the cutter in operative position.

5. In a cutter-head of the character described, the combination of a main body having an abutment Wall With an undercut sloping face adapted to engage and overliea bevelled edge portion of the cutter and having a series of spaced notches at different distances from said Wall, a clamp having an undercut bevelled face adapted to engage and overlie an opposite bevelled edge portion of the cutter and having a heel to iit in any one of said notches depending upon the Width of the cutter, and a bolt having interlocking engagement With said main body and adjustable with the clamp toward and from said Wall and adapted to maintainthe clamp heel in the appropriate notch and to cause the clamp to hold the cutter in operative position.

6. A cutter-head of the character described, comprising in combination, a main body having an abutment Wall against Which a side edge portion of the cutter is adapted to bear, clamping means adjustable toward and from said abutment Wall adapted to engage the opposite side edge portion of the cutter, means adjustable toward and from Said abutment Wall designed to fasten an intermediate portion of the cutter between said edge portions, whereby the same instrumentalities may be employed for holding cutters of different Widths on said cutter-head.

7. A cutter-head of the character described, comprising in combination, a main body having a series of transverse notches andan undercut longitudinal groove, means on said body adapted to engage one side edge portion of a cutter, an apertured clamp designed to engage the opposite side edge portion of said cutter andhaving a heel adapted to enter any of said notches depending upon the Width of the cutter, and a bolt fitting in said groove and clamp aperture adapted to tighten the clamp and maintain it in cutter fastening relation.

8. A cutter-head of the character described, comprising in combination, a main body having a series of transverse notches and an undercut longitudinal groove, an undercut abutment Wall on said body adapted to engage one side edge portion of a cutter, a beveled apertured clamp designed to engage the opposite side edge portion of said cutter with its beveled surface and having a heel adapted to enter any of said notches depending upon the Width of the cutter, and a bolt iittin in said groove and clamp aperture adapte to tighten the clamp and maintain it in cutter fastening relation.

9. A cutter-head of the character described, comprising in combinatioma main body having a series of transverse notches and a longitudinal undercut groove, an undercut abutment Wall onrsaid body adapted to engage one side edge portion of a cutter apertured between its side edges, a beveled apertured clamp designed to engage the opposite side edge portion of said cutter and having a heel adapted to enter any of said Vnotches depending upon the Width of the cutter, a bolt iitting in said groove and clamp aperture and adjustable in the former adapted to tighten the clamp and maintain it in cutter fastening relation, and a second bolt in said groove designed to project through said cutter aperture and hold the intermediate portion of the cutter firmly against said main bod H RRISON J. MITCHELL. 

